The alignment of interconnection points on a towing load and a draft vehicle is usually a difficult process. Very commonly the driver's seat of the draft vehicle is remote from the site of the interconnection point. Examples include the driver's seat in a pick-up truck having a trailer hitch mounted on the rear bumper, and the driver's seat of an aircraft docking vehicle, which seat is generally at the rear of such vehicle while the towing interconnection point is on a tongue extending forward from the front. Even in the docking vehicle example, where the hitch interconnection point may be visible to the driver, a vertical view for precise alignment is not available. Commonly, then, the driver of the draft vehicle must either guess at the proximity of the receiving socket, dismount the draft vehicle for closer inspection and then remount the draft vehicle to adjust its position, or have a second person stand at a strategic location and provide signals. Often, such a second person is not available, and the alternative of guessing and adjusting the position of the draft vehicle is a repetitive and inexact process. Frequently, the process results in the driver of the draft vehicle attempting to manually maneuver the tongue of the towing load to complete the interconnection. Just as commonly, however, such maneuvering is not possible for a single man due to the weight of the towing load.
A number of devices have been provided for assisting the driver in an alignment such as this. In some of the prior art, an attempt to increase the field of vision resulted in the use of a curved reflective surface. See, e.g., Neeley (U.S. Pat. No. 4,905,376), Rutkowski (U.S. Pat. No. 3,762,292) and Strokmeier (U.S. Pat. No. 3,524,701). Such a curved reflective surface merely aggravates the image size problem. Thus, the driver cannot see an image of the trailer hitch ball that approximates the size of the image of the receiving socket until the two are relatively close to each other, and neither image remains fixed in apparent size throughout the operation.
Other efforts to solve the alignment problem include Lowell (U.S. Pat. No. 3,858,966) which employs an indicator element (similar to a weather vane) that points in the direction of adjustment as the draft vehicle approaches the trailer load. This device, however, relies upon a tether to the draft vehicle, requiring at least one entry and exit of the draft vehicle by the driver to hook up the tether once the draft vehicle has been maneuvered to within its range.